How many grams of CaF2 would be needed to produce 1.23 moles of F2?

We see from the chemical formula itself that there is 1 mole of F2 for every 1 mole of CaF2, hence the number of moles of CaF2 is also:

moles CaF2 = 1.23 moles

The molar mass of CaF2 is 78.07 g/mol, so the mass is:

mass CaF2 = 78.07 g / mol * 1.23 mol

mass CaF2 = 96.03 grams